Well, if it's "Jeurasian" week at GNXP, I did have a few things to chip in. First is that the Cochran title is a reference to How the Leopard got his Spots...which is a self-referentially wry dig at sociobiological just-so stories. Nice wordplay there, GC. [1]

Second, just thought I'd link to this decent summary of Jewish genetics research up to 2002:

'The authors are correct in saying the historical origins of most Jewish communities are unknown,' Dr. [Shaye] Cohen [of Harvard University] said. 'Not only the little ones like in India, but even the mainstream Ashkenazic culture from which most American Jews descend.'.... If the founding mothers of most Jewish communities were local, that could explain why Jews in each country tend to resemble their host community physically while the origins of their Jewish founding fathers may explain the aspects the communities have in common, Dr. Cohen said.... The Y chromosome and mitochondrial DNA's in today's Jewish communities reflect the ancestry of their male and female founders but say little about the rest of the genome... Noting that the Y chromosome points to a Middle Eastern origin of Jewish communities and the mitochondrial DNA to a possibly local origin, Dr. Goldstein said that the composition of ordinary chromosomes, which carry most of the genes, was impossible to assess. 'My guess,' Dr. Goldstein said, 'is that the rest of the genome will be a mixture of both.'"

So the upshot is: Y chromosomal lineage from the Middle East, mtDNA from local mothers, and autosomes are yet to be determined. A founder population of males from the Middle East came in, married local females, and practiced endogamy once the community got large enough. Another large contributor to phenotypic resemblance is natural selection effects...in irony of ironies, the Nazis exerted strong selection pressure for blond haired, blue eyed Jews.

Clearly at least some autosomes will have characteristically Ashkenazi signatures, because some of the diseases common to the Ashkenazi are located on autosomes (that is, non-sex chromosomes).

This stuff is also useful for fact-checking Cochran's essay, of course...though I'm too lazy to look up those pathways ;)

Now, a special treat for our GNXP readers:
Intellectual property bending uploads of two papers on the possibility of selection in Ashkenazim. My professional opinion? I think Risch is wrong, though he shouldn't be derided as PC. He did write this good piece last year on the reality of race.

I don't know buy the "lower visuospatial IQ" for Jews. Supposedly it comes from Daniel Seligman's book "A Question of Intelligence", but in my opinion it's unlikely that Jews would have anything like their incredible math dominance (see here) without high visuospatial skills, unless "visuospatial" means something different than "ability to rotate/visualize three dimensional objects".

If memory serves, every one of these mutations is autosomal. As for your point about paternal and maternal ancestries, read the paper more closely. The evidence for local founding mothers is strong in some groups but not for the Ashkenazi.

3/4ths of the Ashkenazi conenxin-26 deafness mutations are a common Middle Eastern mutation, one of the two factor XI mutations is shared with Asian jews, familial mediterranean fever is also found in Sephardic/Asian Jews and some other middle easterners.

Reasonable people estimate that around 80% of Ashkenazi ancestry is Middle Eastern and I have no trouble with that.

And surely the higher IQ of Ashkenazi Jews can be explained by the practice of usury, which gave them more financial resources - thereby allowing the men to pick and choose the best local Slavic women. In other words, the high Ashkenazi IQ comes from Slavic genes.

Even if your slightly lurid theory is basically correct, it begs the question of why the Slavs don't also have average IQs of 115. There might be some heterosis at work, but I still think the primary mechanism is brutal selection pressure for high intelligence plus probably some luck in terms of the genetic material that survived the early medieval population bottleneck. Of course once we have a better understanding of the genetics, we can find out whether the slavic and ashkenazi populations share some IQ-boosting variation that isn't found in other Jewish populations. I bet if they do find such a thing it will be more thoroughly distributed in ashkenazim, though.

One thing I've noticed about the racists who inhabit the web: They don't seem to understand even the basics of gene frequencies. It is possible that alleles for high intelligence in jews came from Poles. It is also possible that gene frequencies in a population can change over time. So it is possible that, no offense meant to anyone at all, the modern Greeks, absent any population inflow/outflow have very different gene frequencies than ancient Greeks, ditto Italians and Romans. I sometimes wonder if selection in Spain for risk-taking, violent men to go to the New World had much of an affect on the societies there.

You're wrong. Just about every Jewish IQ study shows visuospatial skills equal or lower to general European scores, and if you were really tuned in, you'd know this already. It fits the occupational/professional patterns. Moreover, it fits my selective model - they were financiers, not engineers or architects or bowmen. 'g' is one principal component of intelloigence, but visuospatial is another principal component, statistically independent.

If you select for 'g' you get less of other things: this is inevitable.

Really? Like the Mongolians in Mongolia?
I know the eskimos have high visuospatial ability, and its often cited as an environmental influence on IQ, cuz the people citing it aren't very smart I guess. Why don't we use these hbd hotspots to draw students into engineering programs?
Not on the subject of this thread, but has anyone tested native americans for differences in gene frequencies? They are such a small population, probably from only a few waves of migration, that if one tribe/ethnic groups had a seriously different selective environment, we should be able to clearly see adaptations.

It doesn't, I suppose, if the theory is that the Jewish group got some intelligence-boosting genes from the surrounding population and then spread them throughout their community due to the selection pressures already mentioned elsewhere. The point I was trying to make is that you still have to have differences in selection pressure to explain the results, since the influx of local genes was not that large or long-lasting. Eventually genetic analysis will show whether the relevant variation is a lucky mutation, a complementary one from the local population, or a previously rare allele that got widely spread. Or some combination, as seems likely. But in all these cases the critical element is the selection pressure on the community.

The time depth of separation between sub-Saharan Africans and anybody else is much, much greater than the time depth of separation between Europeans and Middle Eastern populations. So the fact that AShkenazi SNPS are a lot closer to European than to African tells you nothing about the extent to which Ashkenazi ancestry is European or Middle Eastern.
Again, the mtDNA study (Thomas et al, AJHG, 2002) clearly shows that many Jewish populations had very few female ancestors. In some populations, like the Bene Israel from India or The Falasha, the mtDNA is clearly local.

But in the case of the Ashkenazi, mtDNA gene diversity is not particularly low (0.973 versus 0.988 among Germans). Thomas says "The pattern in Ashkenazic Jews is of particular interest. Despite the common opinion that this population has undergone a strong founder event, it has a modal haplotype with a frequency similar to that of its host population (9.0% vs. 6.9%), providing little evidence of a strong founder event on the female side." Nor can they tell _where_ Ashkenazi mtDNA comes from. Could be European, could be Middle Eastern.
On the topic of whether the Ashkenazi went through a bottleneck: neither Y-chromosome or mtDNA evidence suggests that. A bottleneck should decrease heterozygosity: I ran 88 loci out of Ken Kidd's database, and the Ashkenazi show no decrease at all; just the same as Russians or Druze. . The Finns show a decrease, Samaritans do - not the Ashkenazi.

I think the Thomas mtDNA study reported no exact matches between Ashkenazi mtDNA haplotypes and those from either Europe or the Middle East. This might very well be the result of genetic drift. At the mtDNA haplogroup level, there is apparently not enough discriminatory power to differentiate between European and Middle Eastern origins.

Haddad, is your reasoning that Aleppo is near Urfa (in Southeast Turkey), the biblical Haran, where Isaac and Jacob are reported to have taken cousins for wives? Interestingly, I have read that Muslim tradition identifies Urfa/Haran as the birthplace of Abraham.